This is an application to investigate the role of NO on the function of mesopontine cholinergic (MPCh) neurons. These neurons project to the thalamus and the basal forebrain and they have been implicated by a number of studies in sleep and attentional states. Considerable evidence suggests that these cells produce NO which functions in some way to regulate their own excitability. The idea is that since NO is a diffusible neuromoduulator it could play a role in coordinating the synchronous activity of a population of neurons thought to play a key role in behavioral state.